GB269779A - Improvements in the recovery of vanadium from solutions - Google Patents

Abstract

269,779. Stevens, R. H., Norris, G. C., and Watson, W. N. Aug. 23, 1926. Drawings to Specification. Ferric vanadate; zinc vanadate; vanadates; zinc sulphate.-Vanadium is precipitated from. solutions containing free vanadic acid by neutralisation, preferably at about 50‹ C., with a, base such as zinc oxide, lime, or limestone in presence of a ferric compound; enough of the latter may be present to effect the precipitation of all the vanadium as ferric vanadate, or a part only may be so precipitated, the remainder being zinc vanadate, if zinc is present or is used as the base. The invention is particularly adapted for the treatment of zinc-vanadium ores; the .latter may be leached with spent electrolyte as usual, but ferrous sulphate be added to reduce the vanadium to the tetravalent state to prevent its precipitation with the impurities which are removed bv the addition of a base in the next step of the process. Phosphorus, if present, may be removed in the manner described in Specification 269,778. Before being precipitated, the vanadium is reconverted to the pentavalent state, as by adding an acid and manganese dioxide, and a ferrous compound may be added at this stage to yield the ferric compound required for the subsequent precipitation. Finally a base is added in a tank fitted with agita.ting- apparatus, the ferric compound being added if not already present, and the precipitate . is filtered. The filtrate, containing the zinc is further purified, if necessary, prior to electrolysis, whilst the vanadium precipitate is washed to remove sulphates either with water, a, solution containing sodium chloride, or dilute acid, in a series of tanks fitted with agitating-apparatus. The product may be used in the production of ferro-vanadium or of vanadium oxide,. A flow sheet for the process is included in the Specification. Specification 269,780 also is referred to.